Spinal Muscular Atrophy

What is Spinal Muscular Atrophy?

Spinal muscular atrophy (SMA) is a disorder that causes weakness and wasting of muscles. The condition may be acquired or hereditary. The hereditary SMA syndromes are genetic diseases that cause motor neurons in the spinal cord to degenerate and die, causing the muscle weakness. There are several types of hereditary spinal muscular atrophy, based on the severity of the disease and when the disease developed. The most severe type (Werdnig-Hoffman disease) presents in infancy; these infants cannot walk and many die of respiratory failure before their second birthday. Kugelberg-Welander disease presents after the age of two and has a variable course. Rarely, hereditary SMA begins in adulthood. Disease presents with muscular weakness in lower more than upper extremities. Progressive respiratory insufficiency may happen due to weakness of respiratory muscles.

Kennedy's disease is also considered a form of SMA.

Who gets Spinal Muscular Atrophy?

Hereditary spinal muscular atrophy is a genetic disorder. The disorder is recessive, meaning a child has to inherit the gene from both parents to be affected. Most patients are affected in childhood, although some forms can affect people much later in life.

How is Spinal Muscular Atrophy diagnosed?

After taking the patient's history and performing a physical examination, a physician may perform a blood test to see if the patient has the genetic flaw causing spinal muscular atrophy. The physician may also perform an EMG.

How is Spinal Muscular Atrophy treated?

There is no definitive treatment for hereditary SMA, Physical and occupational therapy, use of assistive devices and braces are often useful in helping patients cope with the effects of the disease and relieve complications.

More Information

Cure SMA
National Institutes of Neurological Disorders and Stroke
Spinal Muscular Atrophy Foundation
Muscular Dystrophy Association